This study will investigate methodological issues in preterm infant outcomes by applying time series techniques to the analysis of longitudinal data collected in the NICU environment and integrating these single subject results for generalization across individuals. These methodological and analytic techniques will help elucidate the biologic, behavioral, and growth processes of preterm infants and will suggest potential intervention strategies for ameliorating the outcomes of these infants. The five specific aims outlined are to: 1) identify and describe both short- and long-term biobehavioral VLBW and/or VP infant outcomes as they vary over time; 2) describe salient aspects of the NICU micro- environment as they vary over time; 3) investigate the dynamic relationships between biobehavioral VLBW and/or VP infant outcomes and the NICU micro-environment over time; 4) describe the relationships between the characteristics and demographics of VLBW and/or VP infants, parental participation in their infants' care, and infants' biobehavioral outcomes; and 5) interpret the above findings in terms of an eco-technology approach, identifying specific ways in which variations in environmental care might facilitate positive health care outcomes and disease prevention. Sixty-eight preterms whose gestations are equal to or less than 29 wk will be studied from admission until they are 30 wk gestation, or are transferred or discharged. The study variables include gestational age, growth measures, severity of illness, demographics, skin temperature, heart rate, respiratory rate, mean umbilical arterial pressure (for those infants with umbilical arterial lines), oxygen saturation, peripheral blood pressure, behavior as assessed using the Neonatal Individualized Developmental Care and Assessment Program (NIDCAP; Als & Gibes, 1984), pre- and post-NlDCAP salivary cortisol levels, a contextual measurement of the NICU environment, light and sound intensities, sound frequencies, isolette and warmer bed temperatures, and NICU bedspace geography. These variables will be obtained at pre-determined times for each infant. In addition, data pertinent to family visitation will be collected using a daily survey log. At the completion of the study and the infant's hospitalization, the costs of stay during the study period and for the entire hospitalization will be collected from patient accounting. Data will be analyzed using time series analysis to determine how the current NICU environment relates to VLBW and VP infant biologic status, behavior, growth, and parental visitation dynamically. Specific ways, areas, times, and settings, in which variations in treatment might facilitate early problem treatment and/or early problem detection will be suggested and refined using consultation from a neonatologist. The results from this normative research study will be critical for comparing the effects of any changes implemented in neonatal nursing on behalf of optimizing infant growth, development, and well-being in subsequent studies.